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Gut microbes -

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Gut microbes

The average person has 1.5Kg of gut microbes. They affect biology and health. Abnormalities in gut
microbes are linked to the development of disease. Over the coming years, molecular scientists will
discover more of the secrets of each individual gut bug and the links between them and potential


This transcript was typed from a recording of the program. The ABC cannot guarantee its complete
accuracy because of the possibility of mishearing and occasional difficulty in identifying

Naomi Fowler: The first surprise about gut microbes, or gut bugs, is the sheer amount of them, as
Professor Jeremy Nicholson explains.

Jeremy Nicholson: The average person has about one and a half kilograms of gut microbes, so that
has a big influence on your body, and if you totalled up the number it's something like a hundred
trillion microbes inside you. And you only have about ten trillion cells in the whole of your body,
so they sort of outnumber us ten to one in terms of the number of cells. So they have a big effect
on our biology, and also our health. They're extremely difficult to culture by conventional
techniques, so it's only in the last maybe five to ten years that we've really known about their
diversity and how to study them.

Elaine Holmes: There are a million and one different influences that have been associated with the
presence or activity of certain types of gut microflora. For example, people who are born by
caesarean section have a different microflora from natural births. Professor Elaine Holmes.

Elaine Holmes: There's been proved to be a difference between babies that are breast-fed and babies
that are bottle-fed. Other things that are known to affect them are where you live, the type of
food you eat. Even a change of water can affect the equilibrium of the microflora and it can take a
few days to settle down until it reaches a stable level again. Almost any environmental influence
can change your gut microflora.

Naomi Fowler: Until now most drug discovery has targeted the mechanisms in the human body,
re-engineering human cells and signalling pathways inside the body often after disease has been
detected. But scientists now know abnormalities in gut microbes are linked to the development of
disease. So diagnosis becomes predictive and prevention becomes key.

Jeremy Nicholson: There are a lot of diseases that have occurred that have increased in the last
30, 40, 50 years; diabetes, obesity, some sorts of cancers, even neuropsychiatric disorders. What
we know now is the causes of those are not just in our own genome, although some of our own
genetics is involved, but it's the interaction with the environment. And it turns out that in
almost all of those cases there are unusual interactions with the gut microbes. So with our new
technologies we can start to probe those interactions and thus understand how people with certain
genetic predispositions based on dietary and gut microbial interactions may or may not have greater
probabilities of having particular sorts of diseases. So we can look at it from the point of view
of prospective risk, and we can also look at the prospective targets for intervention, whether
those are drugs or indeed dietary.

Naomi Fowler: Apparently before this study only about five people in the whole world had ever had
their gut microbes analysed, is that right?

Jeremy Nicholson: Comprehensively analysed, that's absolutely true. The reason for that is that the
microbiological techniques and the genetic techniques they use are so complicated and expensive,
that you're very restricted on the number of people that can be studied. At the's going
to get cheaper in the future, so in the future we'll be able to study a far greater number of

Naomi Fowler: So you actually analyse their poo?

Elaine Holmes: Yes. What we actually do, our part of it here is to take the urine or the faecal
extract and tie it in with the microbial profiling. We collaborate with a group in Shanghai who
have a very good microbiological department, Professor Li Ping Zhoa. They had already set up a
study on a seven-member family. They had samples, then we offered to do the metabolic profiling for
them and to mathematically link the two, which is the expertise that we have within this group.

Naomi Fowler: And can you tell me what is the significance of all this for drug development?

Jeremy Nicholson: Conventional drug companies are running out of targets. They've found all the
easy drugs to get and they're getting worse and worse at discovering new drugs and in the future
they're going to have to move their business model a bit to try and take into account prevention.
So there'll be a convergence over the next five, ten, fifteen years between what we might normally
consider to be a drug company and what you think of maybe as a nutrition or a lifestyle company.
That may be the business future in this area.

Naomi Fowler: So could we see some time in the future perhaps gut microbe analysis clinics where
people would go in to have a personal analysis of the likelihood of potential diseases. I know this
is a long way in the future, but is this the sort of thing that you're..?

Jeremy Nicholson: Well, at the moment that would be extremely expensive. It would cost hundreds of
thousands of dollars per person. But the technology is moving quickly, so that eventually you'll be
able to get chip-based analyses, so it might come down to a few hundred dollars per person, in
which case you'd get a readout of your personalised gut microbes. It's science fiction at the
moment, but science fiction has a habit of becoming science fact quite quickly these days, so maybe
in ten years' time you will be able to personalise your nutrition, for instance, by knowing what
sort of gut microbes you have, and what the best type of diet-and indeed dietary supplements that
you might want to use-are for the particular individual.

Naomi Fowler: So, 21st century medicine will favour prevention over cure, with a more holistic
approach which diagnoses and treats through diet and drugs which target gut microbe abnormalities.
Over the coming years bio-molecular scientists will discover more of the secrets of each individual
gut bug and the links between them and potential diseases. I've been talking with professors Elaine
Holmes and Jeremy Nicholson at Imperial College London for The Science Show.